Signaling arrangement for telephone lines



Ap 5, 1932. w. H, EDWARDS SIGNALING ARRANGEMENT FOR TELEPHONE LINESFiled April 10, 1951 Tip INVENTOR iVfiEdww ds ATTORNEY Patented Apr. 5,1932 UNITED STATES PATENT caries WILLIAM: H. EDWARDS, OF GREAT NECK, NEWYORK, ASSIGNOR T0 AMERICAN TELE- PHONE AND TELEGRAPH CODIIEANY, ACORPORATION OF NEW YORK Application filed. April 10,

The invention relates to telephone systems and more particularly to theapplication of signal or ringing responsive devices to telephone linesof such systems.

One of the objects of the inventioncon= sists in the provision andapplication to tele phone linesof ringing responsive apparatus whichwill be tuned to respond to a particular frequency but will not respondto frequencies considerably above or below the ringing frequency. Theapplication of a tunedringer to telephone lines will tend to preventfalse ringing due to switchhook operation, testing, dialing, crossringing and other causes. For

-"- example, if the ringing responsive device be tuned to frequencies ofapproximately cycles, false operation on dialing impulses, which may beof the order of 8 to 11 cycles, may thus be avoided. I V

The signaling arrangements of the invention have further application toand advantages with telephone lines of the party type. In such lines,wherein a plurality of subscribers utilize a single line, it has beenthe practice to have the ringers at the various subscribers sets poledand biased by means of springs to aid in making them selective to thesignaling currents applied to the line. It is one of the objects of theinvention to provide ringing responsive devices for party telephonelines, which devices will be selective without the'need of beingspringbiased and Without requiring the use of several signalingfrequencies, thus eliminating the need of bias- 7 ing spring adjustmentsand reducing the maintenance expense caused thereby.

The ringing responsive apparatus of the invention has the furtheradvantage that it may operate with a single gong rather than with twogongs as in former ringers, while at the same time giving a volume ofsound with one gong practica-lly the same as that with two gongs.Consequently, a tuned ringer of the type of the invention has theadvantage of'requiring a relatively small space for a large volumeoutput, as well as having maintenance advantages. Other objects andfeatures of the invention will appear more fully from the detaileddescription thereof hereinafter given.

1931. Serial No. 529,256.

The invention may be more fully understood from the followingdescription, together with the accompanying drawings, in the Figures 1,2 and 3 of which the invention is illustrated. Fig. 1 shows a side viewof a preferred form of the ringing device of the invention. Fig. 2 is acircuit diagram showing the application of the ringer to a four-partyselective line. In Fig. 3 the ringing device is shown applied to anordinary subscribers line.

The ringer shown in Fig. 1 comprises two coils 12 and 13 mounted on abase andhaving pole pieces 14 and 15. Mounted on these pole pieces bymeans of the lock nuts 16 and 17 is a supporting member 18. Thissupport-' ing member holds a stiff reed spring (not shown) to which isaiiixed the clamp 20 which holds the armature 19 and the stem 21 of theclapper 22. This may be termed the armature assembly. A. single gong 23is shown adjacent to the clapper. The permanent magnet 24 is provided asshown. The relatively stiff reed spring and heavy clapper permit thearmature assembly'to-be tuned to a desirable ringing frequency, forexample, 20 cycles, but with slow build up of amplitude on smallcurrents. I The tuning of the armature assembly presents the advantageof preventing false operation of the gong due to switchhook or dialingimpulses transmitted over the line. Tuning of the armature assemblytogether with the feature of slow build up of armature amplitude trave1on small currents presents the further advantage of preventing falseoperation on party lines due to cross ringing currents until thetripping relay operates. On larger currents lasting for the fullduration of the ringing period a strong signal is obtained once fullamplitude is obtained. This is due to the fact that the movement of theclapper is controlled solely by the operation of the armature and thepositioning of the single gong and is not limited by a second gong orstopping devices. When the clapper ismoving away from the gong, the pullon the armature carries the assembly to a point where the force isbalanced by the restoring force of the reed. There is no energy lostexcept that due to windage and internal friction in the reed. When theclapper is at the limit of its stroke, the pull on the armature isreversed and this energy added to that stored in the reed is imparted tothe gong. The tuned effect of the armature assembly results in expendingthe energy for one whole cycle in sounding one gong with double volumerather than sounding two different gongs, each with energy from one-halfcycle of current. In other words, the energy applied to the armatureassembly during its movement away from the single gong is stored in thereed clapper and armature support instead of being dissipated in heatwhen the armature strikes the core as in former types of ringers.v Thisenergy is added to the electrical energy of the re turn stroke and isimparted. to the gong. Ac-

cordingly, the tuned ringer of the invention.

has the further advantage of giving a volume of sound with one gongwhichis practically v the same as that. produced heretofore with twogongs with the further advantage of compactness' of structure.

In Fig. 52. the ringing arrangements of the invention are shown asapplied to a fourparty selective line L Obviously the ringingarrangements of the invention may be applied to other types of partylines. The line L may be connected to a central office 1 at whichseveral typesof current may be applied to the line, such, for example,as current of a ringing frequency, alternating ringing current with adirect current component of either polarity superimposed thereon.switchhook impulses or dialing impulses. The ringers 6, 7 8 and 9 of thetype shown in Fig. 1 are shown directly connected either to the tipor'ring of the line. The ringers are controlled by relays 2, 3. 4 and 5connected across the line in series with condensers and responsive toalternating current. When superimposed ringing current is applied to theline both alternating current and direct current will be transmittedthrough the ringers. When direct current is sent through the ringer, amagnetic bias is given to the armature. shifting the point of rest ofthe armature and clapper assembly to one side or the other, clependingon the polarityof the direct current. The oscillations produced by thealternating current applied at the same time will be very much the sameas for operation on regular alternating current except that the centerof oscillation will be about the point of rest de-' termined by thedirect current. In other words, the clapper may be made to oscillatealong the line A of Fig. 1 when the proper polarity of superimposedringing current is used and will actuate the gong. Then the oppositepolarity of current is used, the clapper will oscillate along the line Bof Fig. 1, and will not strike the gong. Accordingly, if the gongisadjusted so that it will. be struck by the clapper when one polarityofsuperimposed current is used and is out of range of the clapper when theother polarity is used, the ringer arrangements may be used forselective signaling on party telephone lines in the manner abovedescribed.

In Fig. 3 the ringing device of the invention is shown applied to anordinary subscribers telephone line L The ringer is shown as 11 and isbridged across the line L in series with a condenser. The line L isconnected to a central oifice 10. Ringing currents may be applied to theline L from the central office 10 and also current impulses caused bydialing, switchhook and other operations. As has been hereto-forepointed out, if a tuned ringer of this invention is used, falseoperation due to dialing or switchho'ok impulses maybe avoided.

While the invention has been disclosed as embodied in certain specificarrangements which are deemed desirable, it is understood that it iscapable of embodiment in many and other widely varied forms. without,departing from the spirit of the invention. as defined by the appendedclaims.

What is. claimed is:

1. Ina telephone system, a party telephone line, means for applying tosaid line an alternating current with a direct current component ofeither polarity superim posed thereon, a plurality of ringing responsivedevices operatively connected todifierent sides of said line, and aplurality of. relays associated with said line and responsive to saidalternating current for closing the circuits of sand ringing responsivedevices, said ringing responsive devices being of the tuned armatureassembly type and having their operativeness controlled by the polarityof the direct current component applied? to the line.

2. In a telephone system a party telephone line, means for applying tosaid line an alternating current with a direct current com ponent ofeither polarity superimposed thereon, and a plurality of ringingresponsive devices connected to ,difl'erent sides of said line, each ofsaid ringing responsive devices comprising an armature tuned to thefrequency of said alternating current, a single gong, a clapper solelycontrolled by theoperation of said armature and the position of saidgong, and means controlled by the polarity of the direct currentcomponent superimposed on said line for shifting the center ofoscillation of the clapper away from or closer to the gong whereby theoperation of the gong may be controlled.

3. A telephone line, a tuned single gong ringer having an armature withya reed support connected to said line, and means for applying to saidline an alternating current with a direct current component of eitherpolarity superimposed thereon whereby a magnetic bias may be given tothe. armature for shifting the center of oscillation of the armature andclapper assembly to one side or the other depending upon the polarity ofsaid direct current component.

In testimony whereof, I have signed my name to this specification this9th day of April 1931. 1

WILLIAM H. EDWARDS.

